To date almost all efforts to minimize the likelihood of train derailments have concentrated on the maintenance of railway tracks. Unfortunately, this is largely impossible to achieve, due to the thousands of miles of track that must be kept in continuous repair, temperature extremes notwithstanding. Rails are known to expand (run) with heat and contract with cold, which often results in broken bolts, angle irons and even rails themselves. It is, therefore, understandable that no device or system has ever been able to eliminate derailments.
The present invention reflects the conclusion that derailments will always happen, despite all the precautionary devices and efforts made toward eliminating them. Because derailments are inevitable, the second-best objective would be to keep damage and injury to a minimum in any future calamity. Derailments may be inevitable, but the ensuing wreckage can be minimized or even, on occasion, prevented.
After the cars of a train begin to derail, many times the train continues forward for many miles, because detection is delayed for a critical amount of time. Due to the way that railroad tracks are structured, an accident will usually occur at a location most likely to induce the worst damage; such locations are usually at switches, signals, bridge abutments and adjacent track which carry on-coming trains. The vehicles subsequently rip up track, endanger lives and damage any surrounding signals, switches, cars and cargo. Tank cars carrying hazardous chemicals or toxic waste are likely to be ruptured by the derailment, thus spewing their dangerous cargoes.
Train cars are coupled together by large iron knuckles. Beneath these knuckles are situated two hoses of the air-brake system that are connected by conduit throughout the train. The air-brake system is under constant pressure. It is only when the pressure is released that the brakes are applied. When railroad cars derail, the hoses and conduits carrying the compressed air do not always rupture. Only a collision or a voluntary pulling of the emergency cord will activate the air-brake system. Such a system cannot prevent large-scale damage.
As one of its main objectives, the present invention seeks to provide a new safety device that would immediately detect and limit damage and injury due to derailment of a railway vehicle. The invention seeks to alert the engineer immediately of the fact of a derailment and, simultaneously therewith, to initiate an immediate air pressure bleed-off in the braking system. The air pressure is gradually reduced to prevent jack-knifing, and the braking action is applied uniformly throughout the cars of the train. Upon the early sensing of a derailing car, the current invention automatically engages the air-brake system, thus bringing all the cars of the train to a gradual halt. In this manner, impending large wrecks can be avoided and extensive damage curtailed or prevented.
In other words, the invention forestalls or contains damage and injury at the first sign of a derailment problem.
Another objective or the current invention is to provide a device that is simple and reliable, as well as one which operates automatically upon, and in conjunction with, the existing air-brake system. The invention utilizes a skip-jack device to activate the brake system. The skip-jack is gravity force actuated, thus requiring no internal or external mechanism, circuit or power source. This simple gravity device ensures a more reliable activation of the braking system than do other such safety devices.